Effect-directed analysis as a method for quality and authenticity estimation of Rhodiola rosea L. preparations.

Adulterations of food and pharmaceutical preparations are the important global problem. On the one hand, fraud practices are becoming more and more sophisticated while on the other, monitoring and uncovering falsifications are insufficient. One of the most common consumer concern is the quality and authenticity of the purchased products, related to the confidence that they have composition and properties in accordance with the manufacturer's declaration on the label. This refers also to pharmaceuticals potentially delivering great health benefits such as Rhodiola rosea L. supplements. The aim of this study was defining authenticity and possible adulterations of two R. rosea preparations basing on their TLC-bioprofiles and the presence of biomarker compounds characteristic for this plant. The effect-directed analysis (EDA), i.e. TLC hyphenated with micro-chemical and biological assays performed directly on TLC plates followed by HPLC-ESI-MS was used for the bioprofiling of antioxidants, antibacterials, and inhibitors of lipase, acetylcholine, α-glucosidase and tyrosinase as well as for the identification of the biomarkers. The results pointed to the possible adulteration of one of the tested products related to the absence of two rosavins, the most important quality markers of R. rosea.